Seasonality in the Trans-Atlantic Slave Trade

Stephen D. Behrendt(Victoria University of Wellington),
2008

Provisioning-slaving seasons

Seasonality in Atlantic slaving markets linked closely to
food supplies, since merchants, whether African, European, or
American, would not purchase large numbers of people they could not
keep alive. There were distinct provisioning-slaving seasons in
Atlantic regions dependent upon a short rainy season and a staple
crop. In more diversified early modern economies, often those with
fewer dry months (and hence more evenly distributed rainfall), food
production and labor requirements on farms became less seasonal.
Provisioning-slaving seasons ebbed during rainy planting months and
increased during and after dry season harvests. After crops were
harvested and stored, African merchants sold enslaved farmers and
provisions to coastal middlemen who, in turn, sold these captives
to ship captains.

In Africa, Upper Guinea (from Senegal to the Ivory Coast)
and the Bight of Biafra had marked provisioning-slaving seasons. In
Senegal and Gambia, millet stocks increased in March-May before the
summer rains. May-July was correspondingly the greatest quarter in
the Senegambian slave export trade—three times greater than in the
September-November quarter. Along the Sierra Leone/Windward Coasts,
the rice-slave season began in November and supplies of food and
people began to dwindle in late April. In spring 1751, south of
Sierra Leone, Liverpool captain John Newton VoyageID 90350,
the author of “Amazing Grace,” purchased late-season rice and
slaves. He remarked on April 30th in his logbook, held today at the
National Maritime Museum (UK), “the season is so far advanced.”
Sierra Leone/Windward Coast slave exports from March to May almost
doubled totals from June to August. In the Bight of Biafra, the
season’s first yams arrived in markets in July and August; the peak
harvest occurred in October, and supplies remained until February
or March. September-November slave exports doubled those totals
from June-August. Fewer dry months along the Gold Coast or Bight of
Benin enabled farmers to often double-crop maize and other cereals.
Given greater food supplies, slave exports exhibited less of a
seasonal trend. Traders also did not identify provisioning-slaving
seasons along the West-Central African coast. With few foodstuffs
available for export overseas, the link between harvest cycles and
slave supplies is weakest in the South Atlantic African slaving
markets.

The timing of dry season grain and cash crop harvests
regulated the New World demand for enslaved African labor. The
sugar producing West Indies and Guianas imported more slaves during
the December-May corn and cane harvests. In Brazilian
sugar-producing centers, such as Bahia, the provisioning-slaving
season centered on the drier November-February quarter. During
three months of the harvest season, slave import figures ranged from
twenty-nine percent of annual totals (Cuba, Pernambuco, Bahia) to
forty-four percent (northwest Jamaica). In the smaller
non-sugar-growing regions of North and South America, captains
disembarked comparatively large numbers of slaves in-season during
rainier months. Chesapeake tobacco planters only demanded new
migrant farmers during the April-May spring rains, when men and
women transplanted tobacco stalks to the fields, and in
June-August, before harvesting and curing. The autumn corn harvest
provided food stocks to sustain workers forced to produce the
annual tobacco crop. In the rice-growing Carolina/Georgia
Lowcountry, Surinam, and Maranhão, planters purchased twice as many
workers during the four in-crop months.